The present invention relates generally to gain control circuits wherein the amplification of an audio frequency signal is automatically controlled electronically and more particularly to a gate circuit which dynamically verifies whether gain change is desirable and then gates the operation of the gain control circuit accordingly.
The present invention is applicable to any form of electronic gain control circuit where the amplification of an audio frequency signal is automatically controlled through electronic means. Such circuits may be found in dynamic range compression systems, amplitude limiters, dynamic range expanders, signal gates, amplitude leveling systems, gain platform controllers and other such circuits.
Circuits which control to some extent gain control circuits in audio signal processing systems are known in the art and are usually referred to by the names "silence gate", "release gate", or "gain gate". Such circuits generally compare the program audio level to a fixed, or set, reference level, and open or close the discharge path of a capacitor in the gain determining portion of the automatic gain system.
The present invention, on the other hand, rather than looking at program audio and comparing it to a fixed reference level, compares two instantaneous dynamic characteristics within the program audio to determine a "yes"-"no" decision which is then used to allow charge, or discharge of the storage capacitor, or other medium, in the gain determining system.